1. Field of the Invention
The present invention relates to a battery connector which is useful for, for example, charging a battery, and more particularly to a battery connector in which an engagement piece disposed on a contact member is engaged under a preload with an engagement face of a housing.
2. Description of the Prior Art
A conventional battery connector of this kind is disclosed in PCT National Patent Publication No. 2001-502837. The disclosed connecter will be described with reference to FIG. 9 or 10.
FIG. 9 is a section view of the conventional battery connector, and FIG. 10 is a perspective view of a contact member which is used in the conventional battery connector.
In the battery connector, as shown in FIG. 9, a meandering contact member 210 is housed in a housing 200 in which the lower end is placed on a board face of a circuit board 100. As shown in FIG. 10, the contact member 210 is formed into a meandering shape in which three slender plate piece portions are continuously integrated with one another through two flexible portions 216, 217 that are arcuately protruded. As shown in FIG. 9, a mountain-like projection 212 which is formed in the plate piece portion of one end side of the contact member 210 is projected through an oblong opening 205 that is formed in the upper wall of the housing 200, and its top is formed as a contact 213 which is to be in elastic contact with a battery terminal (not shown). A fix piece 214 which is fixed to a wall 201 of the housing 200, and a soldering terminal 215 which is foldedly formed to be connected to a pattern on the circuit board 100 are formed in the plate piece portion of the other end side of the contact member 210. The lower flexible portion 216 is fitted into a hole 203 which is formed in another wall 202 of the housing 200, and the upper flexible portion 217 is opposed to the wall 201.
An end portion of the mountain-like projection 212 of the contact member 210 is bent in a substantially perpendicular manner toward the inner side (in the illustrated example, the lower side) of the mountain-like projection 212. The folded end portion is provided with a rectangular engagement piece portion 220 which is laterally projected. An end face of the engagement piece portion 220 is in elastic contact under a preload with an engagement face 206 which is formed by a wall face of a peripheral portion of the opening 205, to be engaged therewith. The degree of projection of the mountain-like projection 212 from the opening 205 of the housing 200 is restricted by the configuration where the engagement piece portion 220 is in elastic contact and engaged with the engagement face 206 under a preload as described above.
In the battery connector, in an initial state where no external force acts on the contact member 210, the engagement piece portion 220 is overlappingly in elastic contact with the engagement face 206 of the housing 200 as shown in FIG. 9. When a battery D is to be charged, the battery D is attached to and detached from the connector.
In the operation of attaching the battery D, the battery D is inserted into the connector in the direction of the arrow C1 of FIG. 9 which is perpendicular to the compression direction (vertical direction) of the meandering contact member 210. As a result, the battery D is caused to slide over the mountain-like projection 212 to retract the mountain-like projection 212, so that a terminal of the battery D is pressed against the contact 213 of the projection to be in elastic contact therewith. At this time, the contact member 210 is compressed, the mountain-like projection 212 is retracted as indicated by the arrow c1 to be pressed into the opening 205, and the engagement piece portion 220 separates from the engagement face 206. As a result of the retraction of the mountain-like projection 212, a situation in which an arcuate portion 221 of the one end of the contact member 210 strikes against the wall 202, or the flexible portion 217 strikes against and rubs with the wall 201 sometimes occur. By contrast, in the operation of detaching the battery D, the battery D is separated from the connector in the direction of the arrow C2 of FIG. 9 which is perpendicular to the expansion direction of the meandering contact member 210. At this time, the contact member 210 which has been compressed by the flexural deformation is expanded, and the mountain-like projection 212 is displaced as indicated by the arrow c2, whereby the mountain-like projection 212 is projected from the opening 205. As a result, the engagement piece portion 220 is engaged with the engagement face 206, and the connector is returned to the initial state to be prepared for the next use.
As shown in FIG. 11 illustratively showing problems of the conventional example, in the conventional example, a situation possibly occurs where the operations of attaching and detaching the battery causes the end face of the engagement piece portion 220 to rub with the engagement face 206 in the direction of the arrow d1 or d2 while maintaining the elastic contact with the engagement face. When such a situation occurs, there is the possibility that the engagement piece portion 220 which is a metal portion shaves the engagement face 206 which is a synthetic resin portion, or that the thin engagement piece portion 220 is caught by the engagement face 206 to be deformed.
When the engagement piece portion 220 shaves the engagement face 206 or the engagement piece portion 220 is deformed, the housing 200 is reduced in strength to be easily cracked or deformed, or the deformation of the engagement piece portion 220 causes the engagement piece portion 220 not to be engaged with the engagement face 206, so that the engagement piece portion 220 is projected from the opening 205. As a result, the performance required in a battery connector cannot be exerted.